RT Journal Article SR Electronic T1 Do newborn infants exhale through the CPAP system? Secondary analysis of a randomised cross-over trial JF Archives of Disease in Childhood - Fetal and Neonatal Edition JO Arch Dis Child Fetal Neonatal Ed FD BMJ Publishing Group Ltd and Royal College of Paediatrics and Child Health SP 232 OP 236 DO 10.1136/archdischild-2022-324462 VO 108 IS 3 A1 Gunnarsdottir, Kolbrun A1 Falk, Markus A1 Baldursdottir, Sonja A1 Donaldsson, Snorri A1 Jonsson, Baldvin A1 Drevhammar, Thomas YR 2023 UL http://fn.bmj.com/content/108/3/232.abstract AB Background During nasal continuous positive airway pressure (nCPAP) treatment in neonates, leakage is inevitable and can lead to reduced distending pressure in the lungs of the infant. In current practice, neither leakage nor expiratory flow is measured, which makes it difficult to assess if exhalation is through the device or entirely through leakages.Objective To examine if infants treated with nCPAP exhale through the CPAP system.Design and setting Secondary data analyses from the ToNIL trial on leakages during nCPAP treatment. We retrospectively examined respiratory curves for the 50 infants included in the trial, using NI LabVIEW 2015. Each infant was measured with both prongs and nasal masks. A flow recording was classified as exhalation through the system if more than 50% of all expirations showed reverse flow, each for a minimum duration of 0.1 s.Patients 50 infants were included, born with a mean gestational age (GA) of 34 weeks, median birth weight of 1948 g and mean age at measurement 6.5 days. Inclusion criteria were CPAP treatment and a postmenstrual age (PMA) of 28–42 weeks.Results In our measurements, 32/50 infants exhaled through the CPAP system in at least one recording with either nasal mask or prongs. Leakages exceeding 0.3 L/min were seen in 97/100 recordings.Conclusions During nCPAP treatment, infants can exhale through the CPAP system and leakage was common. Measuring expiratory flows and leakages in clinical settings could be valuable in optimising CPAP treatment of infants.Trial registration number NCT03586856.Data are available upon reasonable request.